System.Drawing.Drawing2D.GraphicsPath.ReverseSubpathAndAdjustFlags C# (CSharp) Method

        static void ReverseSubpathAndAdjustFlags(int start, int end, List<byte> old_types, List<byte> new_types, ref bool isPrevHadMarker)
        {
            // Copy all but PathPointTypeStart
            if (end != start)
                new_types.AddRange (old_types.GetRange (start + 1, end - start));

            // Append PathPointTypeStart
            new_types.Add ((byte)PathPointType.Start);

            Debug.Assert (new_types.Count == end + 1);

            var prev_first = old_types [start];
            var prev_last = old_types [end];

            // Remove potential flags from our future start point
            if (end != start)
                new_types[end - 1] &= (byte)PathPointType.PathTypeMask;

            // Set the flags on our to-be-last point
            if ((prev_last & (byte)PathPointType.DashMode) != 0)
                new_types[start] |= (byte)PathPointType.DashMode;

            if ((prev_last & (byte)PathPointType.CloseSubpath) != 0)
                new_types[start] |= (byte)PathPointType.CloseSubpath;

            //
             		// Swap markers
             		//
            for (int i = start + 1; i < end; i++) {
                if ((old_types [i - 1] & (byte)PathPointType.PathMarker) != 0)
                    new_types [i] |= (byte)PathPointType.PathMarker;
                else
                    //new_types[i] &= ~PathPointType.PathMarker;
                    // Can not take compliment for negative numbers so we XOR
                    new_types [i] &= ((byte)PathPointType.PathMarker ^ 0xff);
            }

            // If the last point of the previous subpath had a marker, we inherit it
            if (isPrevHadMarker)
                new_types[start] |= (byte)PathPointType.PathMarker;
            else
                //new_types[start] &= ~PathPointType.PathMarker;
                // Can not take compliment for negative numbers so we XOR
                new_types[start] &= ((byte)PathPointType.PathMarker ^ 0xff);

            isPrevHadMarker = ((prev_last & (byte)PathPointType.PathMarker) == (byte)PathPointType.PathMarker);
        }